Azo dyestuffs



Patented Aug. 12, 1952 AZO DYESTUFFS Victor S. Salvin,Irvington, and John R. Adams, Jr., Summit, N. J., assignors to Celanese Corporation of America, a corporation of Delaware No Drawing. Application February 21, 1949,

Serial No. 77,687

4 Claims; (Cl. 260-487) This invention relates to azo dyestuii's, and re-.

An object of this invention is to provide improved azo dyestufis or dye bases which, when diazotized and coupled with suitable developers, dye cellulose acetate or other organic derivative of cellulose textile material in desirable blue shades fast to light and to acid fading.

Another object of this invention is the provision of azo dyestuiis capable of dyeing cellulose acetate or other organic derivative of cellulose textile materials in blue shades which are dischargeable to a clear, white color.

A further object of this invention is the production of cellulose acetate or other organic deriva tive of cellulose textile materials dyed with said dyestuffs.

Other objects of this invention will appear from the following detailed description.

We have found that azo dyestuifs dyeing cellulose acetate or other organic derivative of cellulose textile materials in dischargeable, generally blue, shades may be obtained by diazotizing a monoazo dye base of the following general formula:

wherein n is to 4, X is -COOH or CONH2, and Y is hydrogen, methyl, ethyl, propyl, methoxy, ethoxy or a propyloxy group and coupling the diazotized compound with a developer. While various developers may be employed, we have found that the most satisfactory results are obtained, particularly for the production of completely dischargeable dyestuffs dyeing in dark blue shades, employing developers of the following formula:

wherein R. is hydrogen, or a methyl, ethyl, or propyl group, and R is a methyl, ethyl, propyl, hydroxyethyl, hydroxyp-ropyl or dihydroxypropyl group. While diazotization of the dye base and coupling with the developer may be carried out to yield our novel dyestuffs in substance, it is particularly advantageous to carry out the diazotization and coupling on the textile material being dyed. This is done by first basing the fabric or other textile material with the monoazo dye base, which is of course a dye itself, diazotizing the monoazo dye on the dyed textile material and then coupling the diazotized base with the developer to form the desired,dischargeable disazo dyestufi'.

Thus, in preparing our novel azo dyes, the monoazo dye base is formed by diazo-tizing pnitroaniline and coupling it with the proper intermediate. As examples of said intermediates, there may be mentioned 3-amino-4-methoxyoxanilic acid, 3-amino-4-methoxy-malonanilicacid, 3-amino-4-methoxy-oxanilamide, 3-amino- 4-methoxy malonanil'amide, 3 amino-4-methoxy succinanilic acid, 3 amino 4 methoxysuccinanilamide, S-amino 4 methoxy glutaranilic acid, 3-amino-4-methoxy glutaranilamide, S-amino-oxanilic acid, 3 amino 4 ethyloxanilic acid, 3 amino-4-ethoxy-oxanilic acid, 3-amino 4 ethyl or methyl-oxanilamide, 3- amino-4-ethoxy-oxanilamide, 3-amino-4-ethy1 or methyl-succinanilic acid, 3 amino 4 ethyl or methyl malonanilic acid, 3-amino 4 ethyl or methyl-malonanilamide, 3-amino-4-ethoxy succinanilamide, B-amino 4 ethyl or methyl-glutaranilic acid, 3 amino-4-ethoxy-glutaranilamide, 3 amino 4 propoxy-oxanilic acid, 3-amino 4 propoxy-oxanilamide, 3-amino-4- 'propoxy-succinanilic acid, 3-amino 4 propoxysuccinanilamide, 3-amino-4-propoxy-glutaranilic acid, B-amino 4 propoxy-glutaranilamide, and 3-amino-4-methoxyadipanilic acid or -adipanilamide.

As suitable developers which may be coupled with the monoazo dye formed by coupling pnitroaniline with any one of the intermediates, examples of which are given above, there may be mentioned 3 acetylamino dimethylaniline, 3- acetylaminodiethylaniline, 3 acetyla'mino-dihydroxyethyl aniline, 3-acetyalamino-dipropylaniline, 3-acetylamino-di-hydroxypropyl aniline, 3 propionylamino-dimethylaniline, 3-propionylamino diethylaniline, 3 propionylamino dihydroxye'thyl aniline, 3 propionylamino-dipropylaniline, 3 propionylamino di hydroxypropyl-aniline.

In dyeing cellulose acetate or other organic derivative of cellulose textile materials, such as fabrics, with our novel dischargeable dyestuffs, the

fabric is dyed with the monoazo dye base and the dyed fabric obtained is then diaz-otized and cou.- pled with the developer in a separate bath. The.

may also be employed, the fabric being passed through the dyebath and then through a padding mangle adjusted to permit a predetermined amount of dye base to remain thereon. The mechanica'lly impregnated or padded material may then be aged or steamed to cause the dye base i to penetrate thoroughly. After equilibrium shade on the dyed fabric has been reached, the latter is then preferably rinsed or scoured to remove extraneous dyestuff.

' The diazotization of the dye on the dye-based fabric is then effected and. is preferably carried out at low temperature, preferably below 25 C., in an acid diazotization bath. Sulfuric acid is usually employed in the diazotization reaction due to the desirable thermal stability of the diazonium salt. The diazotization may be carried out on a Winch or jig or in any other suitable mechanism for circulating the dye-based fabric and effecting the desired coupling with the developer employed.

The diazotized fabric may be entered into a cold coupling bath and the temperature raised rapidly or else coupling may be effected in a bath which is at about the desired reaction temperature. Coupling may be completed in about 1 to 2 hours at a temperature of 40 to 60 C. After the coupling is completed, all of the excess developing agent on the fabric should be removed, preferably by means of a suitable scour. The scour removes all superficially held dyestuif, developer and dispersing agent which may have adhered to the fabric. The dyed fabric is then rinsed; dried and finished to prepare it for discharge printing.

7 In order to discharge the novel polyazo ground color with which the fabric is dyed, it-is treated with a discharge paste which is applied locally,

for: example by printing or stencilling, in the desired pattern. The discharge pastes. comprise essentially a metal sulfoxylate formaldehyde, such as zinc sulfoxylate formaldehyde which is acid in reaction or sodium sulfoxylate formaldehyde which is basic in reaction. The metal sulfoxylate formaldehyde compounds are reducing agents and split the polyazo dyestuffs at the diazo groups and convert them to colorless compounds which may be Washed away completely to leave a clear white pattern. In addition to the sulfoxylate formaldehyde, the discharge pastes usually contain a thickening agent such as textile gum, hydroxyethyl cellulose or gum tragacanth, and a penetrant such as an alkali metal thiocyanate which is, in effect, a swelling agent for the cellulose acetate or other organic derivative of cellulose textile material. Where an illuminated discharge is desired, the discharge paste will also contain a dyestuff which is either resistant to reduction and is itself a dye for the cellulose derivative material or one which can be reversibly oxidized after being vatted to the leuco form. In general, the vat dyestufis are used for illumination since these dyestuffs have the desired quality of being capable of reversible 4 oxidation after being vatted or reduced to the leuco form. The vat dyestuffs are applied to the fabric mixed in the discharge paste and, thus, careful control of the pattern may be achieved. The methods of discharge printing and illuminated discharge printing are well known in the art.

In order further to illustrate our invention but without being limited thereto, the following examples are given:

Example I 69 parts by weight of p-nitroaniline are dissolved in a solution consisting of 180 parts by weight of concentrated hydrochloric acid (sp. gr.

1.19) in 150 parts by weight of water by heating at to C. The hot solution is then added directly to a well-stirred mixture of 250 parts by weight of ice and 250 parts by weight of water. To this suspension is then added a solution of 36 parts byweight of sodium nitrite in 140 parts by weight of water cooled to 5 to 10 C. The excess nitrite is destroyed with urea. The diazotized solution is then added slowly with stirring to an aqueous solution of parts by weight of 3-amino-4-methoxy-oxanilic acid cooled to 5 to 10 C. Stirring is continued for 1 hour at 10 C. and the azo dyestuff formed filtered and washed. A yield of 100 parts by weight of the azo dyestuff p-nitro-benzene-azo-B-methoXy-4- amino-6-oxanilic acid are obtainedb v About 1 part by weight of the above azo dyestuif is dispersed in a dyebath consisting of 50 parts by weight of soap, 200 parts by weight of Turkey red oil, 5000 parts by weight of water and .20 parts by weight of sodium chloride. 100 parts by weight of a cellulose acetate fabric are entered into the above bath heated to a temperature of 80 C., and maintained therein for 1 to 2 hours. The dyed fabric is then rinsed with water. The dye-based fabric is then entered into a dyebath consisting of 5000 parts by weight of water, 15 parts by weight of sodium nitrite and 7.2 parts by weight of concentrated sulfuric acid and the azo dye diazotized by maintaining the fabric therein for 30 minutes at 15 to- 20 C. The fabric is rinsed and then entered into a coupling bath at 30 C. consisting of 5000 parts by weight of water and 15 parts by weight of 3-di-hydroxyethyl-amino-acetanilide. The coupling bath is then heated to 40 C. for 30 minutes and then 60 C. for an additional 30 minutes.

The cellulose acetate fabric obtained is dyed a navy blue shade which is dischargeable toa clear, permanent white. A discharge paste which is satisfactory consists of 12.5 parts by weight of sodium sulfoxylate formaldehyde, 12.5 parts by weight of sodium thiocya-nate, 40 parts by weight of textile gum and 35 parts by weight of water. The paste is applied to the dyed fabric in a predetermined pattern by means of engraved printing rolls. The pasted fabric is passed into an ager and steamed for 20 to 30 minutes to reduce and discharge the navy blue ground color. The discharged fabric is then soaped and the amine reduction products formed during the discharge are removed. The fabric is then rinsed, washed and finished. A navy blue fabric having a clear, white discharge pattern is obtained. The discharge pattern. remains white permanently. The navy background color is fast to light, washing and acid fading.

Example II A cellulose acetate fabric is dyed with the dye base p-nitro-benzene-azo-3-methoxy-4-amino- B-succinanilic acid, which dyebase is obtained by a coupling reaction as described in Example I. Dyeing is effected by immersing 100 parts by weight of the fabric in a dyebath, at 25 C. for 15 seconds to 1 minute, consisting of 700 parts by weight of 95% ethyl alcohol, 300 parts by weight of water, 100 parts by weight of sodium thiocyanate and 30 parts by weight of the above azo dyebase. The dye-based fabric obtained is then diazotized as described in Example I and the diazonium salt coupled on the fabric with 3-di-hydroxyethyl-amino-acetanilide to yield a fabric dyed in a navy blue shade. The blue dyestufi is readily discharged to a clear white with a discharge paste containing sodium sulfoxylate formaldehyde.

Example III A cellulose acetate fabric is dyed with the dye base p-nitro-benzene-azo-3-methoxy-4-amino- 6-succinanilamide in the manner described in Example I. The dyed fabric is then diazotized and the diazotized dyestuff on the fabric coupled with 3-di-hydroxyethyl-amino-acetanilide. The fabric is dyed a heavy navy blue shade which is dischargeable to a clear white with a discharge paste comprising zinc sulfoxylate formaldehyde.

While the novel dyestuffs of our invention have been described more particularly in connection with their application on cellulose acetate textile materials, they may also be applied with equally satisfactory results on textile materials having a basis of other organic derivatives of cellulose. Examples of other organic derivatives of cellulose are cellulose esters such as cellulose propionate, cellulose butyrate, cellulose acetate-propionate, cellulose acetate-butyrate and cellulose ethers such as ethyl cellulose and benzyl cellulose. Other textile materials, such as nylon or vinyon, may also be dyed by said novel dyestuffs.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit or our invention.

Having described our invention, what we desire to secure by Letters Patent is:

1. Disazo dyestuffs of the following general O OH:

I NQZ-OMNQMNG QEOH NH-(fi-CQOH l ra-( rem o 3. The disazo dyestuff I NoTQmNQmNONmmoH 4. The disazo dyestuff OCH;

NHfJCHgOHgCl)NHg NH-C-CH: 0 t

VICTOR S. SALVIN. JOHN R. ADAMS, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,289,413 Ellis July 14, 1942 2,289,414 Ellis et a1 July 14, 1942 

4. THE DISAZO DYESTUFF 